Magnetic drive for conveyer belts



July 27, 1954 F. F. KOLBE ET AL 2,684,753

MAGNETIC DRIVE FOR CONVEYER BELTS Filed May 10 1952 eooumm oooonm ooooo P O O O 0 0 O U U U U 0 9 12 4 12 0 9 22 u I L 36 58 w 19 2'0 +5 0 INV 1012s. M F5 Patented July 27, 1954 N ITED STATES ATEN-T OFFICE 'MAGNETIC DRIVE FOR CONVEYER'BELTS Application May 10, 1952, Serial No. 287,226

3'Claims. '1 The present invention relates to conveyors and 7 to means for driving same and'is particularly directed to magnetic drives for steel conveyor 1 belts.

Fabric and composition conveyor belts have long been used in many industries for transporting materials. Conveyors are particularly well adapted to modern mass production and provide substantial advantages over other methods and means of material transfer. Fabric and composition belts are, however; subject to wear and fraying due to the rubbing of the edges of the belt against sideguiding members, misalignment of the belt upon its supporting rollers, wear and strain imposed by the material being transferred, and so on. A further disadvantage of fabric and composition belts is that they stretch during use, necessitating the utilization of belt tighteners and the like.

.To overcome the stated disadvantages of fabric and composition belts, metallic belts and composition belts with a metallic base have been proposed and are rapidly coming into use in various industries. Metallic belts present various problems with regard to the driving thereof, which problems are exaggerated by the desire in many industries to increase the length and size of various conveyor runs. While short lengths of beltmaybe conveniently driven in a conventional manner-by'rotating'one of the sup I port and guide rollers therefor, long lengths of belt, particularly metallic belt," cannot be "elliciently and economically driven in thismanner. The problem of driving the conveyors has resulted in a curtailment of the length of individual runsandof the adoption of metallic 1 belts.

An object of the present invention is to overcome the stated problem by providing efiicient and economical means for driving conveyor belts of any desired length of run, which means exert tractive drive efiort substantially uniformly throughout the belt rather than at a localized point; as has been customary.

Bearing in mind that short conveyor runs, not w required to support substantial load, may readily be driven by one of the rollers supporting and guiding same, it is an object of the present invention to provide conveyor belt driving means in the form of a plurality of small endless belt nunits, the belts oithe individual units being driven in a conventional manner and having tractive cooperation x-with the conveyor belt.

, sistance to wear and "stretching, are best adapted .for use as conveyor belts, a more particular object of the present invention is to provide'drive means of the character described, wherein tractive cooperation-between the rindividual drive belts and the main belt'is attained magnetically.

Accordingly, an. object of the, present invention is the provision of a magnetic drive for ferrous conveyor belts.

A further object of the present invention is the provision of individual units formagnetical- 1y driving a steel conveyor belt, each unit comprising a relatively short endless ferrous metal belt, rollers for supporting the belt, means for driving the belt, anda plurality of electro-magnets adapted to create a magnetic field passing through the belt of the unit and the'conveyor belt so as to attract the two belts to one another and effect substantially positive engagement therebetween.

Other objects'and advantages of the present invention will become apparent from the followstantially on the line 3-3 of- Figure 2; and

.Figure 4 is across sectional view, similar to Figure 3, on an enlarged scale, of a second em .bodiment of the drive unit of the present invention.

Referring now to the-drawings, and particularly to Figures 1, 2 and 3; a steel conveyor carrier belt is indicated at it, which may be of any suitable or desired length and which is supported and guided at its ends by a pair of main support rollers l2. The carrier belt it is reaved over and guided by the rollers l2' and a plurality of smaller support rollers 14 disposed beneath each run of the'belt. The carrier belt it is adapted to be drivenmagnetically by a plurality of magnetic drive units It of the present invention.

Each of the-driveunits It comprises an endless traction belt 29 suitably reaved over and guided by'a pair of end rollers 22. rollers 22 is provided with a sheave adapted for One of the the reception ofa pulleybelt 24, reaved over the. sheave and over a pulley ZBadapted to bedriven by an electric motor 28 provided with a standard gear reducer 30. in'certain instances, wherein the load on the carrier-belt l t or on the traction belt 28 is substantial, suitable gears may be Since steel and ferrous metals, due to their restituted for thesheave on the roller and for the pulley 26 and there may be substituted for the pulley belt-26a chain engaged with the gears in In. As is shown in the drawings and as is preferable, the upper run of the traction belt 28 is in engagement with the lower surface of the upper or load-carrying run of the carrier belt H3.

Between the end or main rollers 22 of each drive unit l6, the carrier belt l and the traction belt 20 are supported by a plurality or rollers 3 The rollers may be disposed in any desired arrangement as will appear more fully hereinafter, but as is shown in Figure 3, the rollers 34 may simply be disposed in two parallel rows with their axes parallel to the horizontal plane of the belts l0 and 2D. Disposed immediately below each of the rollers 34 is an electro-magnetic roll 38 wound about an armature 39, the armature having an arcuate upper face conforming substantially to the peripheral curvature of the rollers 34. Each of the electro-magnets is mounted upon and magnetically connected at one side thereof by means of an iron bridge 40.

While the drawings and the previous description are directed solely to the apparatus of the present invention, it will be appreciated that the carrier belt Ill and the drive units [6 may be supported in any conventional manner in the relationships statedl For example, the axles of the supporting rollers l2 and H! for the carrier belt It may be suitably secured to a conventional supporting ladder for the carrier belt Hi. The support rollers 22 and 34 of each of the drive units l6 are preferably mounted on brackets suitably secured in any conventional manner to the supporting ladder for the carrier belt ID. The iron bridge carrying the electro-magnets 38 may also be mounted on a bracket suitably secured to the supporting ladder for the carrier belt I (I. If preferred, the rollers 22 and 3 of each drive unit [6, and the motor 28 and bridge 40, may be supported together and adapted to be secured as a unit to the supporting ladder for the carrier belt.

To provide a magnetic attraction between the carrier belt I!) and the traction belt 20 of each unit, the belts l0 and 20 are preferably formed of steel of a high magnetic permeability and the rollers 34 and the iron bridge 49 are also magnetically permeable. Hereinafter, for convenience, the magnetically permeable belts it and 2t, rollers 34 and bridge 40 are sometimes referred to as magnetic. The coils 38 of the electro-magnets are, preferably layer wound D. C. shunt coils connected in parallel. Accordingly, the magnetic circuit or flux path between the electro-magnets 38, at one side therof, will be through the iron bridge ll! and, at the opposite side thereof, will pass directly through the carrier belt l0 and the traction belt at to effectively lock the two belts together for simultaneous movement. In view of the foregoing, it will be appreciated that the present invention essentially comprises a steel traction belt adapted to be brought into engagement with a steel carrier belt, supporting means for the belts and spaced magnetic means having a flux path therebetween passing through the traction belt and the carrier belt.

The motor 28 of each of the units H is preferably an alternating current motor having a power source separate from the electro-magnets 38 and may be provided with any suitable control means to vary the speed of operation thereof.

In instances wherein the carrier belt It is curved, as when supported by inclined rollers so that the belt presents a concave carrying surface, the rollers 34 should be inclined so that the drive belt 20 conforms to the carrier belt 10. However, when a plurality of drive units 18' are utilized with a concave carrier belt, it is impractical to provide cylindrical end rollers for the belt 28 since same would result in flexation of the belts l0 and 20 to planar surfaces at each end of each drive unit. Accordingly, revision of the embodiment of the invention shown in detail in Figure 3 is required.

Referring now to Figure 4, a second embodiment of the drive unit of the invention, particularly adapted for use with concave carrier belts, is shown. In accordance with the broader aspects of the invention, the general relationship shown in Figure 1 is adhered to with either embodiment of the drive unit, so that a plurality of drive units l6 are provided for the carrier belt It. To provide a concave carrier belt, the end rollers l2 suitably may be cylindrical rollers, but the support rollers 14 for the upper run of the belt comprise two spaced parallel rows of oppositely inclined rollers so that the upper run of the belt I!) is required to assume a dished or concave configuration. To maintain the concavity of the belt N3, the traction or drive belt of the drive units must be disposed to conform to the belt Hi. In Figure 4, we have shown an embodiment of the drive unit of the present invention, preferred for driving concave carrier belts, which is generally similar to the drive unit previously described. In Figure 4, parts similar to parts and elements of the drive unit previously described are indicated by like reference numerals with the suflix a.

As shown, each of the drive units comprises a pair of endless traction belts 20a, each suitably reaved and guided by a pair of end rollers 22a. One roller of each pair may suitably be provided with substantially the same drive means as previously described, wherein an electric motor 28 is provided. To drive both of the belts 26a, an end roller 22a of each belt may be provided with a separate drive means, the motors being synchronized, or the belts may be driven by a single motor through two pulley arrangements or by a suitable driving connection between adjacent rollers 22a. The rollers 22a are mounted on inclined axes, the same as the rollers I l, so that the two belts 20a are inclined toward one another and maintain the concavity of the carrier belt l0. Each of the belts 20a is so disposed that one run thereof engages the upper run of the carrier belt H], as is shown in Figure 4.

Between the end or main rollers 2211, each traction belt 20a is supported by a plurality of rollers 34a. The rollers 34a are preferably disposed on an inclination the same as that of the rollers 22a and I4 so as to properly support and guide the respective traction belts 20a. and the carrier belt l0. The provision of oppositely inclined side rollers 3401. establishes and maintains the dished or curved configuration of the carrier belt H3, so that material carried thereby will have little tendency to move laterally oh the belt. Disposed immediately below each of the inclined side rollers 34a is an electro-magnetic coil 38a, substantially identical to the electro-magnets previously described. Each of the electro-magnets is mounted upon and magnetically connected at one side thereof by means of an iron bridge 40a, which is provided with an arcuate upper face conforming substantially to the curvature of the belt it). It will be appreciated that the carrier belt [0 and the drive units IS may be supported in any conventional manner in the relationships stated, as outlined hereinbefore.

In many installations it may prove desirable to provide a central support in the drive units for the carrier belt it. To this end, we preferably provide a plurality of horizontally disposed sup porting rollers 20; disposed in a row centrally of and parallel to the rows of rollers 34a. If desired, the rollers 520. may suitably guide a supporting belt i lol reaved over the rollers 2 2a. and suitable end rollers sea. Likewise, the embodiment of the invention shown in Figure 3 and described hereinbefore may include similar supporting means. The rollers 42:; and 46a may suitably be journaled on axles common to the axles of the rollers 34a and 22a, respectively, or may be supported in other conventional manners.

To provide a magnetic attraction between the carrier belt iii and the traction belts 29a of each unit, the belts lb and Zea are preferably formed of steel of a high magnetic permeability, the side rollers Eda and the iron bridge dim are also magnetically permeable, and the middle rollers 22a and the belt lsa are non-magnetic. Hereinafter, for convenience, the magnetically permeable belts lb and 26a, rollers and bridge tea are sometimes referred to as magnetic. As will be apparent, the magnetic circuit or flux path between the electro-magnets 38a, at one side thereof, will be through the iron bridge its and, at the opposite side thereof, will pass directly through the carrier belt it and the traction belts Zda to effectively lock the traction belts to the carrier belt for simultaneous movement. In view of the foregoing, it will be appreciated that the middle row of rollers 52a and the belt merely comprise supporting means and are not essential to the magnetic drive of the present invention. Accordingly, it will be appreciated that the second embodiment of the present invention essentially comprises a pair of steel traction belts adapted to be brought into engagement with a steel carrier belt, supporting means for the belts and spaced magnetic means having a flux path therebetween passing through the traction belts and the carrier belt.

While the relationship described and shown is preferably adhered to, it will be appreciated that the belts 246a could comprise a single belt reaved over the various pulleys 22a and 34a.

From the foregoing, it will be appreciated that the present invention provides a conveyor belt and a plurality of individual drive units for driving the conveyor belt, each of the units being adapted for association with and disassociation from the conveyor belt and adapted for separate replacement or use. By providing a plurality of drive units, the tractive efiort exerted on the carrier belt is uniformly distributed throughout the length of the belt so that same is positively driven and so that the belt is not subject to the tensile load normally exerted on conveyor belts by virtue of driving same at a localized point, as has been customary. By providing individual drive units adapted to be associated in any numher with a conveyor belt, the present invention is particularly adapted for the driving of extremely long runs of conveyor belt, which may be of any length desired in any particular installation, the number of units being determined by re length of the carrying run of the belt and the character of the material to be transferred by the carrier belt.

While we have described what we regard to be preferred embodiments of our invention, it will be apparent that various changes, rearrangements and modifications may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

We claim:

1. A conveyor con prising an endless steel carrier belt of high permeability and a plurality of drive units therefor, each unit comprising an endless steel traction belt of high permeability havign one run thereof in engagement with said carrier belt, a pair of rollers supporting said traction belt, means for dr ving one of said rollers to drive said traction belt, a plurality of supporting rollers disposed in two spaced parallel rows to the inner side of said one run of said traction belt and at opposite sides thereof, each of said rows of supporting rollers being inclined with respect to one another and each of the rollers in the rows being to of magnetic material, electro-magnet disposed adjacent each of the supporting rollers in said rows, an iron bridge supporting and magnetically connecting said electrc-magnets at one side thereof, whereby said electro-magnets have a flux path through the supporti. g rollers rows an through said traction belt and said carrier belt to magn tically connect said belts, whereby said carrier belt is driven by the tra tion belts of said drive units.

A magnetic drive unit for a conveyor belt formed of magnetic material, said unit comprising an endless steel traction belt of high permeability having one run thereof adapted to be in engagement with the conveyor belt, a pair l of said traction belt, the outer rows of said supporting rollers being inclined with respect to one another and each of the rollers in the rows being formed of magnetic material, the rollers of the middle row being disposed substantially parallel to the mean plane of said belt and being non-magnetic, an electro-magnet disposed adjacent each of the supporting rollers in the outer rows, and an iron bridge supporting and magnetically connecting said electro-magnets at one side thereof, whereby said electro-magnets have a flux path through the supporting rollers in the outer rows and through said traction belt whereby the traction belt is adapted to be magnetically connected. with the conveyor belt.

3. The drive unit of claim 2 wherein the surface of each electro-magnet adjacent a roller is concentric with the surface of the roller and wherein the surface of the bridge on that side which is close to the belt substantially conforms to the surface presented by the group of rollers, with the longitudinal axis of each electro-magnet being normal to the axis of its adjacent roller.

References Cited in the file or" this patent UNITED STATES PATENTS Number Name Date 996,022 Lindhard June 20, 1911 1,561,063 Dunlap Nov. 10, 1925 2,594,342 Pettyjohn Apr. 29, 1952 2,655,248 Buccicone ct. 13, 1953 FOREIGN PATENTS Number Country Date 235,207 Great Britain Nov. 26, 1925 

